Abstract
In higher plant chloroplasts, specific C residues on some transcripts are subject to C-to-U RNA editing. Though plant chloroplast genomes generally have 20-30 RNA editing sites, there appear to be no conserved motif around them, suggesting that those editing sites each are recognized by site-specific cis-trans factors. In this study, we examined the diversity of those trans-factors with the aid of an in vitro RNA editing system of tobacco chloroplasts and UV cross-linking experiments. We previously showed in psbE RNA that the editing site and cis-element both are recognized by a site-specific 56 kDa protein. Here we show that the editing sites of rpoA-1, rpoB-2, and rpoB-3 are bound by distinct site-specific factors. Comparisons of these protein factors with those bound to respective cis-elements are in progress. Based on these findings, we would like to discuss about the organization and diversity of trans-factors involved in chloroplast RNA editing.
